1. Technical Field
The present invention relates in general to the controlled mixing of gases and, in particular, to an improved system, method, and apparatus for controlling the delivery of two gases through a high temperature artifact without undesirable mixing of the gases during transmission through the artifact.
2. Description of the Related Art
In some industrial applications, two gases must be mixed and reacted in a controlled atmosphere at very high temperatures. However, maintaining separation between the two gases with components fabricated from non-reactive materials is a significant obstacle for at least two reasons. First, high temperature materials (such as graphite) are often porous and require a seal or coating to form a gas barrier. This is a material surface type seal, or material seal. Secondly, manufacturing and assembling high temperature artifacts into a geometry that contains gas flow channels that do not allow gas mixing has not been accomplished previously. One of the greatest difficulties is sealing at the interfaces between components (e.g., a component-to-component seal). In prior art designs, the separate gases were channeled past both material seal areas and component interface seal areas. Sealing technology for either type of these areas is significant, and sealing both types of areas together has eluded both design and manufacturing technology to date.
For example, U.S. Pat. No. 6,132,079, to King, discloses a multi-path mixing apparatus for mixing water and an herbicide at low temperature. However, that patent utilizes many separate components that form a multitude of interfaces and seals that inevitable permit some level of mixing. Similarly, U.S. Pat. No. 2,815,532, to Braunlich, discloses a spinneret mixing element analogous interfaces and seals in the working zone. These devices simply cannot form high temperature seals for highly reactive gases. When gas flow is used for chemical reaction to facilitate a process (e.g., semiconductor processing; especially etching), the difficulty often becomes that of handling and conveying the reactive chemical gases to the process area. Additionally, the reaction itself requires high temperature materials such as carbon, glass, or ceramics to convey the gases and not react or interfere with the process. Thus, an improved solution for controlling the delivery of two gases through a high temperature artifact without undesirable mixing of the gases during transmission through the artifact would be desirable.